No you haven't...one of the taps is connected to the cold water supply, and you connect the filling loop (flexible pipe) to the other tap which in turn is connected to the heating (radiator) supply. Ideally you turn the cold supply on first, then open the other tap to introduce water into the system, hence increasing the pressure as seen on the gauge. Turn the second tap off first, followed by the cold supply one, and disconnect the filling loop pipe. Does this make sense?
John
April 2009